XML 48 R36.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Long-Term Debt Senior Notes (Details) - USD ($) $ in Thousands | Mar. 31, 2018 | Dec. 31, 2017
--- | --- | ---
Debt Instrument [Line Items] |  |
Senior Notes, net of unamortized deferred financing costs | $ 2,770,979 | $ 2,769,663
6.50% Senior Notes Due 2021 [Member] |  |
Debt Instrument [Line Items] |  |
Senior Notes, interest rate, stated percentage | 6.50% |
Senior Notes, face amount |  | 344,611
Unamortized deferred financing costs | $ (2,483) | (2,656)
Senior Notes, net of unamortized deferred financing costs | $ 342,128 | 341,955
6.125% Senior Notes Due 2022 [Member] |  |
Debt Instrument [Line Items] |  |
Senior Notes, interest rate, stated percentage | 6.125% |
Senior Notes, face amount |  | 561,796
Unamortized deferred financing costs | $ (5,505) | (5,800)
Senior Notes, net of unamortized deferred financing costs | $ 556,291 | 555,996
6.50% Senior Notes Due 2023 [Member] |  |
Debt Instrument [Line Items] |  |
Senior Notes, interest rate, stated percentage | 6.50% |
Senior Notes, face amount |  | 394,985
Unamortized deferred financing costs | $ (3,525) | (3,707)
Senior Notes, net of unamortized deferred financing costs | $ 391,460 | 391,278
5% Senior Notes Due 2024 [Member] |  |
Debt Instrument [Line Items] |  |
Senior Notes, interest rate, stated percentage | 5.00% |
Senior Notes, face amount |  | 500,000
Unamortized deferred financing costs | $ (5,380) | (5,610)
Senior Notes, net of unamortized deferred financing costs | $ 494,620 | 494,390
5.625% Senior Notes Due 2025 [Member] |  |
Debt Instrument [Line Items] |  |
Senior Notes, interest rate, stated percentage | 5.625% |
Senior Notes, face amount |  | 500,000
Unamortized deferred financing costs | $ (6,487) | (6,714)
Senior Notes, net of unamortized deferred financing costs | $ 493,513 | 493,286
6.75% Senior Notes Due 2026 [Member] |  |
Debt Instrument [Line Items] |  |
Senior Notes, interest rate, stated percentage | 6.75% |
Senior Notes, face amount |  | 500,000
Unamortized deferred financing costs | $ (7,033) | (7,242)
Senior Notes, net of unamortized deferred financing costs | 492,967 | 492,758
Senior Notes [Member] |  |
Debt Instrument [Line Items] |  |
Senior Notes, face amount | 2,801,392 | 2,801,392
Unamortized deferred financing costs | (30,413) | (31,729)
Senior Notes, net of unamortized deferred financing costs | $ 2,770,979 | 2,769,663
Senior Notes [Member] | 6.50% Senior Notes Due 2021 [Member] |  |
Debt Instrument [Line Items] |  |
Senior Notes, interest rate, stated percentage | 6.50% |
Senior Notes, face amount | $ 344,611 | 344,611
Senior Notes [Member] | 6.125% Senior Notes Due 2022 [Member] |  |
Debt Instrument [Line Items] |  |
Senior Notes, interest rate, stated percentage | 6.125% |
Senior Notes, face amount | $ 561,796 | 561,796
Senior Notes [Member] | 6.50% Senior Notes Due 2023 [Member] |  |
Debt Instrument [Line Items] |  |
Senior Notes, interest rate, stated percentage | 6.50% |
Senior Notes, face amount | $ 394,985 | 394,985
Senior Notes [Member] | 5% Senior Notes Due 2024 [Member] |  |
Debt Instrument [Line Items] |  |
Senior Notes, interest rate, stated percentage | 5.00% |
Senior Notes, face amount | $ 500,000 | 500,000
Senior Notes [Member] | 5.625% Senior Notes Due 2025 [Member] |  |
Debt Instrument [Line Items] |  |
Senior Notes, interest rate, stated percentage | 5.625% |
Senior Notes, face amount | $ 500,000 | 500,000
Senior Notes [Member] | 6.75% Senior Notes Due 2026 [Member] |  |
Debt Instrument [Line Items] |  |
Senior Notes, interest rate, stated percentage | 6.75% |
Senior Notes, face amount | $ 500,000 | $ 500,000

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion. Senior note holders are paid off in full before any payments are made to junior note holders. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_SeniorLongTermNotes
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.17) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_UnamortizedDebtIssuanceExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_DebtInstrumentAxis=sm_A650SeniorNotesDue2021Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=sm_A6.125SeniorNotesDue2022Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=sm_A650SeniorNotesDue2023Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=sm_A5SeniorNotesDue2024Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=sm_A5.625SeniorNotesDue2025Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=sm_A6.75SeniorNotesDue2026Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=us-gaap_SeniorNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |